Daisuke NAKAGAWA

Making of Powder Avalanche Aazard Map by Numeric Calculation

Tokuzou HOSOYAMADA


The region on the Sea of Japan side of winter is an eminent area of very heavy snowfall also in the world. In Japan , person of about 20 percent of all population lives in area of very heavy snowfall. And about 70% of the country in Japan is forestry and mountainous area where villages and structures are also located. Therefore, it is necessary to consider the danger of the avalanche in Japan.
The amount of the snowfall is very many in Niigata Prefecture especially. The amount of the maximum snowfall exceeded four meters in 2006. So Niigata Prefecture has potential damages to natural disasters by powder snow avalanches. The Yamakoshi located in the center part in Niigata Prefecture received big damage to the avalanche prevention hedge due to the Tyuetsu earthquake in 2004. So the extensive damage from the storm might occur when the avalanche is generated in Yamakoshi. Then, it aimed to make the hazard map of the avalanche with a simulator of the powder avalanche.